Harvesting lettuce and other leafy food plants is a labor-intensive process. The economically valuable part of lettuce and similar plants is a compact core of leaves growing close to the ground in densely-packed rows. The core may be surrounded by loose outer leaves that may be discarded when the plant is harvested. Lettuce and similar leafy plants are easily crushed or bruised by rough handling. Harvesting may be accomplished by manually cutting each plant close to the ground with a knife without cutting through the core, one plant at a time. When a plant is harvested, it may be preferable to remove some of the outer, loose leaves wrapped around the compact core. Cutting a plant too high above the ground surface may cause damage to the economically valuable core by severing too many leaves. Cutting a plant too close to the ground surface may cause the knife to contact the ground, after which the knife may need to be cleaned to protect cut plants from contamination. The knife may need to be sharpened after ground contact.
The person harvesting the plants works for extended periods in a stooped or bent-over position and must take care not to damage the harvested plant or cause personal injury with the harvesting knife. Because the work is physically demanding, when an entire field is ready for harvesting, it may be difficult to quickly find enough people skilled in the preferred harvesting method to collect the crop before produce spoils or is damaged by the weather. Furthermore, because the harvested plant is a food item, it would be preferable to minimize the risk of contamination by avoiding human contact with the plant before delivering it to a buyer.